#!/bin/sh
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2007-2023  IPFire Team  <info@ipfire.org>                     #
#                                                                             #
# This program is free software: you can redistribute it and/or modify        #
# it under the terms of the GNU General Public License as published by        #
# the Free Software Foundation, either version 3 of the License, or           #
# (at your option) any later version.                                         #
#                                                                             #
# This program is distributed in the hope that it will be useful,             #
# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
# GNU General Public License for more details.                                #
#                                                                             #
# You should have received a copy of the GNU General Public License           #
# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
#                                                                             #
###############################################################################

. /etc/sysconfig/rc
. ${rc_functions}

eval $(/usr/local/bin/readhash /var/ipfire/main/security)

case "${1}" in
	start)
		# Nothing to do here when SMT is forced on
		if [ "${ENABLE_SMT}" = "on" ]; then
			exit 0
		fi

		# Nothing to do when SMT is not enabled or not supported anyways
		if [ "$(</sys/devices/system/cpu/smt/control)" != "on" ]; then
			exit 0
		fi 2>/dev/null

		# Do not disable SMT inside virtual machines
		if running_on_hypervisor; then
			exit 0
		fi

		# Disable SMT when the processor is vulnerable if SMT is enabled
		for vuln in $(ls /sys/devices/system/cpu/vulnerabilities/*) ; do
			if [ -r "${vuln}" ] && \
					[[ "$(<${vuln})" =~ "SMT vulnerable" ]]; then
				# Disable SMT
				boot_mesg "Disabling Simultaneous Multi-Threading (SMT)..."
				echo "forceoff" > /sys/devices/system/cpu/smt/control
				echo_ok

				# No need to check any further when we have disabled SMT already
				break
			fi
		done
		;;

	*)
		echo "Usage: ${0} {start}"
		exit 1
		;;
esac
